Process for composite casting



Aug. 18, 1931. 1 SUGIMURA- ETAL 1,819,722

PROCESS FOR COMPOSITE CASTING Filed Nov. 22, 1929 1 Patented Aug. 1.8, 11931 UNITED-.STATES PATENT OFFICE SUGIMUR, OF SHI'BA KU, TOKYO, ANI) KWANICHl MAGARISAWA., OF 'I'SURUIMI- XU, YOKOHA'MA, JAPAN, k.ASSIGN'ORS T0 MEIJ'IRO YASUMOTO, OF YOKOHAM'A, JAPAN PROCESS .FOR COMPOSITE CASTING ApplicationV led November 22, 1929. Serial No. 409,138.

Our inventionrelates to a novel process for casting two different kinds Aof metals melted vand* mixed together and the one sheathed on Uthe other. The invention consists in thattwo kinds alloys which dofnot readily ma e alloy with eachother, onefmetalhaving qualities of less ,specific gravity, higher melting point and greater surface tension, thanthe otherwhich of course, must have more specific gravity, lower melting-point, less surface tension than the former Vand moderate adhesivev power as regards the former, when melted jointly or separately and mixed together` and poured into the mould, the metal of lower melting point is sheathed uniformlyover the metal of higher melting point at any desired thickness.v

The object of the inventionis to provide a novel, processfor metal sheathingby merely .casting two metals, one of which forms the coreand the other forms the sheath, both pro- If vided with aforesaid relative qualities. Thus the Wholesurfaceof a cheap-and strong metv al, sucha-sl iron, may be coated to any desired thickness with tity of a costly andexcellent metalsuch as copper, in a veryv` simple and economical way r so that the vdefect of the `core Vmetal may be' a0 remedied while keeping its excellent nature,

and the merit ofthe sheath metal may be satisfactorily developed. f According ,to the present invention, two kinds of simple metals or alloys of av different nature are melte'djointly or separately and are .mixed together in a vessel and then poured `into the mould.

With a peculiar relation, the two metals do not become mingled together in the mould 40 but the core metal becomes. evenly sheathed with the other metal.. l

The' :relations ybetween' twov metals, which form the essential feature of the present invention, are thatthey differ in -their melting point, specific gravity, and surface tension; that they never make an alloy even though' theyare stirred up at the Apouring temperature ofthe metal of the -higher meltingpoint that the metal of the highermelting point has lessspecic gravity and greater of simile metals or iron (l) la om rativel smallA uan-` C Pa Y q of th surface tension, and that the sheath metal has a moderate adhesivapower to the core metal when they are brought in contact at melting state.

The accompanying drawings illustrate the method of carrying out the present invention,

Fig.`1 shows a sectional side elevation of metals melted together in a vessel. Fig. 2 is asectional side elevation showing the vessel inclined so as to pour molten metalsinto a mould. n l

From evidence, it is believed that 'when two kinds of metals which do not make alloy with each other, are melted and mixed together in a vessel, the metal of greater specific gravit .l metal of less specific gravity takes the upper position, l-and in the combination of two metalswhich have special qualities as above mentioned, `the boundary line between the different metals is formed as shown in Fig. '1. molten cast iron (specific avity about 7.2, melting point about. 1300"` and cop er (specific gravity 8.8, melting point 1083 are put togetherk in the. same vessel, the cast first tends to take a spherical shape e least surface area while the copper (2) at the bottom, by its adhesive, power to cast iron Aand to the surface of the vessel rises up between .the cast iron (1) and the inner surface of the vessel (3) due to the capillary 80 .action caused between them as in the case of water and glass tube, because of the fact that the surface tension of cast iron (l) is greater' than that of copper (2) at the same temperature. In this manner, if molten metal in the vessel is not'too deep, the copperV ascending v 2, and results in a special casting, the core of which is iron sheathed with copper. e IThe temperature of molten metals, especially at the time of pouring into the mould (casting temperature) and the depth of 100 molten metals in the vessel affect the performance of the sheathing action. Therefore there are certain necessary conditions for the accomplishment of the said sheathing action as follows 1. Two metals to be used for sheathing purpose should differ in their specific gravity and melting point between less specific gravity and higher melting point, the other with greater specific gravity and lower melting' point.

2. Two metals should not make alloy with each other at their casting temperature. Even if they are stirred up in the same vessel they should soon separate from each other after stirring stops.

3. Two metals should be adhesive to each other at casting temperature, provided they never make alloy.

4. The sheath metal should have less surface tension relative to the core metal at the same temperature, in other words, the sheath metal should have far more fluidity than the core metal at the same temperature.

5. The sheath metal should have its best fluidity down to the Vlowest temperature, forming an unbreakable coating down to solidification.

Combination of simple metals or alloys fulfilling the above essentials are such as cast iron (iron alloys) and copper or copper al; loys; cast iron and lead; cast iron and tin; cast iron and other non-alloying heavier metals; zinc and lead; aluminium and lead etc., the former of each combination'formingf the core metal and the latter the sheath.

It is rather rare to find a combination of metals which completely satisfy the above essentials, most metal generally lacking one or more of the important qualities. Moreover, when simple metals or alloys are melted, oxides of metals or slugs formed at the surface of molten metals give hindrance to the perfect formation of the metal sheath.

Thus it becomes nessary to add lsome auxiliary agents for supplementing or augmenting the desired quantities and preventing the undesirable reactions. In view of preventing the oxidation of molten metals, one or more deoxidizing agents, such as aluminium, phosphorus, ma-gnesium and ar Senio may be added into the molten metals before being poured into the mould. For removing slugs and protecting the surface of the molten metals, one or more fluxes, such as ammonium chloride, borax, alum, and chalk may be used.

In the following, a practical example for carrying out the present invention is explained:

Gray or white cast iron is first melted and then 5to 50 percent of bronze is added thereto.

To the molten mixture, the amount of surface tension and being which is called one hundred percent, the

following percentages of auxiliary agents are added.

After the above procedure is rformed, the mixture is stirred up and a ter having remained at rest for a while is poured into the mould. .n

Having now particularly described and ascertained the nature of our said invention and ,in what manner the same is to be performed we declare that what we claim is.

1. A process for casting two different kinds of metals with one metal acting as a core and the other metal as a surrounding sheath, said metals having the propert of not alloyin-g with each other, one metal aving less specic gravity, higher melting point and greater surface tension than the other and the other metal having greater specific gravity, lower melting point and less rovided with moderate adhesive ower to t e former, and

/having a good liui ity and .being adapted to form a strong'sheath when solldified; said process consisting in mixing and meltin said metals together in Aa vessel while stirred, then main at rest or a while thereupon pouring them into a mould and permitting them to solidify, thereby forming a sheathing of the metal of lower melting point around the metal of higher melting point.

2. In a process for casting two different kinds of metals as set forth in claim 1 in which the metal of higher melting point is selected from iron and the metal of lower melting point is selected from a group consisting of copper, copper alloys, lead and tin.

3. In a process for casting two different kinds of metals as set forth in claim 1 in which the metal of higher melting point is selected from zinc and aluminium and the ing ermitting said metals to re/ metal of lower melting point is selected from l u lead and lead alloys.

4. A process for casting two different kinds of metals as set forth in claim 1 in which the metals are selected from a group consisting of east ironcopper, copper alloys, lead, tin, zinc, aluminium and lead alloys are mixed, melted and stirred together with a suitable quantity of auxiliary agents containing phosphorus arsenic, borax, ammonium chloride, aluminium powder and chalk powder.

5. A process for casting non-alloying metals to form a core of one metal and a sheathing of the other metal, which process consists 1n melting from 5% to 50% of cast iron with 95% to 50% bronze thereby forming :L the following amounts of auxiliary agents: 0,01% to 0.03%. phosphorous, 0.002% to 0.003% arsenic, 0.03% to 0.06% borax, 0.10% to 0.60% aluminium and 0.015% to 0.025% chalk powder; then stirring saidlagents well in the mixture to rest a suitable length of time, thereupon pouring the mixture into a mould and permitting it to solidify thereby forming a core with a, surrounding sheathing.

In testimony whereof We have aixed our sig-natures.

IHEI SUGIMURA. KWANICHI MAGARISAWA.

unalloyed mixture; then adding'm v 

